AP Biology Questions on Phylogenetic Trees and Cladograms

📚 Quick Study Guide

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• Phylogenetic Tree: A visual representation of the evolutionary relationships between different species, genes, or populations.
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• Cladogram: A specific type of phylogenetic tree that shows the branching order of lineages, focusing on the sequence of evolutionary events.
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• Node: Represents a common ancestor in a phylogenetic tree or cladogram.
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• Branch: Represents the evolutionary lineage leading to a particular taxon.
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• Sister Taxa: Groups of organisms that share an immediate common ancestor and are each other's closest relatives.
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• Rooted Tree: A phylogenetic tree with a designated root, indicating the most recent common ancestor of all taxa in the tree.
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• Unrooted Tree: A phylogenetic tree without a designated root; shows relationships but not the direction of evolution.
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• Monophyletic Group (Clade): A group of organisms consisting of a common ancestor and all of its descendants.
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• Paraphyletic Group: A group of organisms consisting of a common ancestor but not all of its descendants.
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• Polyphyletic Group: A group of organisms that do not share an immediate common ancestor.
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• Key Steps to Constructing Phylogenetic Trees/Cladograms:
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  • Identify homologous traits (shared traits due to common ancestry).
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  • Analyze data (morphological, genetic, etc.).
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  • Use software to construct the tree based on the data.
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  • Evaluate and refine the tree based on additional evidence.

Practice Quiz

1. Which of the following best describes a phylogenetic tree?
   1. A diagram that shows the geographical distribution of species.
   2. A diagram that represents the evolutionary relationships among organisms.
   3. A table that lists the characteristics of different organisms.
   4. A chart that shows the ecological interactions between species.
2. What does a node represent in a phylogenetic tree?
   1. An extinct species.
   2. A current species.
   3. A common ancestor.
   4. A mutation.
3. What are sister taxa?
   1. Taxa that live in the same geographic location.
   2. Taxa that are morphologically identical.
   3. Taxa that share an immediate common ancestor.
   4. Taxa that belong to different kingdoms.
4. A monophyletic group includes:
   1. A common ancestor and some, but not all, of its descendants.
   2. Organisms that are not closely related.
   3. A common ancestor and all of its descendants.
   4. Organisms that share similar characteristics due to convergent evolution.
5. Which of the following is used to construct phylogenetic trees?
   1. Random chance.
   2. Homologous traits.
   3. Analogous traits.
   4. Environmental factors.
6. What is the main difference between a rooted and an unrooted phylogenetic tree?
   1. A rooted tree shows the direction of evolution, while an unrooted tree does not.
   2. An unrooted tree shows the direction of evolution, while a rooted tree does not.
   3. A rooted tree shows genetic relationships, while an unrooted tree shows morphological relationships.
   4. There is no significant difference.
7. What is a paraphyletic group?
   1. A group that includes all the descendants of a common ancestor.
   2. A group that excludes some of the descendants of a common ancestor.
   3. A group of unrelated organisms that resemble each other.
   4. A group that includes species from different domains.